Improvement in sun-dials



L. I. TRUEG.

Sun'Dial. No. 100,691. Patented March 8,.18'70.

To all 1071,0111, itmcty concern:

[UNITED STATES PATENT OFFICE.

L. IGNATIUS more, or sr. VINGENTS, PENNSYLVANIA.

5 IM PROVEM ENT IN' SUN-BDIALS.

Specification forming part of Letters Patent No. 100,69]; dated March 8,1870.

Be it knownthat I, L. IGNATIUS TRUEG, of

St. Vincents, in the county of 'Westmoreland and State of Pennsylvania,have invented certain new and useful Improvementsin Hcli-' orama; and Ido hereby declare that the following is a full, clear, and exactdescription thereof, reference being had to the ,accompa nying drawings,and to the letters of reference marked thereon, making a part of thisspeciiication. i l i l l The nature of my. invention consists in theconstruction and arrangement of an instrument by which the degrees'oflatitude and the sunltin'ie and clock time is measured, and whichinstrument I call the heliorama.

p In order to enable others skilled in the art to which my inventionappertains to make and use the same, I will now proceed to describe itsconstruction and operation, referring to the View of the plate whoseshadowmeasures the sun time. l i v My instrumentthe helioramais composedof two instrumentsthe helioclisis, tomeasure the. declination of the sunfrom the equator, and consequently the degrees of latitude; and thehemerophora, by which the shadow of the sun time is measured.

A represents the b2LSBI116IliJ-2lu plate of wood 1 orany other suitablematerial, having a recess in its upper side for the insertion of, acompass wherewith the instrument is adjusted.

l The needle of the compass has to coincide with y the line N S on thebed A, so that the north pole of it shows toward N, thus bringing the:

sides, of the bed due north and south and the,

ends east and west. It is self-evident that the basement or bed A has tobe put level when the instrument is set up "for use. a

At each end of the bed A is placed a side piece, B, perpendicular withthe bed. The lower parts of these side pieces have nearly the widthof'the bed or basement. The higher are narrower, having a hole whereinthe pins or axles c a'of the middle piece, 0, are revolving. i

On the outside of the side pieces, B B, are

arcs L L, with degrees marked thereon, one

for the latitude and the other for the height of the celestial equator,the arms a a being each provided with a finger, b, for indicating thesame. A V

G is the middle piece or plate, revolving upon the pins a a in the sidepieces,- BB. Cross wise ou the plate 0 is placed a graduated are,

D, called the cliseologet. It is graduated so that degree 0 is in themiddle, and from this degrees are counted on both sides up to 25.Strictly required, however, are only 23%, because the declination of thesun on the solstices does not exceed said number of degrees.

E is the equatorial gnomon, formed of a semicircular brass plate of thesame radius as the arcof the cliseologet D. The gnomon E is providedwith two feet, which are inserted in the plate G. The two arcs D and Ebiseet each other at right angles, so that a radius perpendicular withthe diameter or base of the gnomon E will stand perpendicular with theare or cliseologet D at degree 0, and its lower end, being the center ofthe semicircular gnoniomwill touch that are on which th degrees aremarked V When the instrument is set up for use, the i plate must be putlevel, and the compass has to shownorth and south, as indicated by theletters N From this it appears that the gnomon E, or rather its diameteror base,isin the direction east and west, and since it follows theequator is called the equatorial gnomon. It must be remarked that the.de grees of latitudeon the western side piece, B,

are laid out thus, that the are L, on which the degrees are measured,has its center in the center of the pin a; and, further, in thedistribution of thedegrees one-half degree (thirtythree minutes) must belost, so that on the place where 89 27 should come 90 will be marked.The. reason for this will appear hereinafter. For convenience sake, thesurface of the middle pie(e or plate, 0, bears a list of the dates ofthe year, with thedegrees of the de clination of the sun marked oppositethe re spective dates. In case the degree of latitude the indicator 1)shows the degree on the are L of the western end piece, B. The arc L onthe opposite end piece is grac'luated in prethe same manner, except thatthe degrees run cisely in the opposite direction, so that when theindicator shows on the latitude side the indicator on thecelestial-equator side will show 90. The sum of the latitude and theheight of the celestial equator is always equal to ninety degrees. Theshade of the sun cast by the gnomon LE on the cliscologet D indicatesthe declination of the sun from the equator, north or south. During theseason when the sun is actually south of the equator the shade fallsnorth of degree 0 on the cliseologet; but during the season on which thesun is north of the equator the shade falls south; but in case thedegrees of latitude of the respective places are not known, then thelist on the plate 0 has to be consulted. Suppose we have the th ofFebruary. The list shows that on this date the declination of the sunamounts 14.4". Having adjusted the instrument with regard to north andsouth, &c.', Ithen turn the middle pieee,-C, untilthcshadow of the sunis cast on the said degree north of dcgree 0. After this I look 011 theare L. IVha-t degree is indicated thereon by the indicator? The verysame is the degree of latitude of the place.

The advantages of this part of my inven tion are that the helioelisisshows the declination of the sun on the different seasons, and it doesthis not only on the mid-day hour, but

on every h0urforenoon and afternoon. Its

greatest advantage, though only a consequence of the first, is this,that it shows the degrees of latitude in case they are not known. Thehelioelisis will, for this reason, be of great service to mariners.\Vhen used on the 'sea, it has to be kept in its direction (north andsouth) by means of a great magnet. It might be asked how the effect ofthe refraction oi the sunbeams in our atmosphere is corrected. By thesimple means that on the distribution of the degrees on the are Lthirty-three minutes arelost, as described above. The refraction of thesun is, at 10, 10"; at 21; at 33", and increasing until at it is 33.Another point remains to be corrected, if deemed necessary. The sun,when casting a shadow, does so not from its center, but from the outlineof its disk. In order, w, to get the shadow, as it were, cast from thecenter, the radius of the sun-disk, which is sixteen minutes, must beadded to the degrees of latitude, which can be effected by subtractingthem in the gradature of the are L. So that, with this secondcorrection, 90 will be marked where 90(16+33)-that is, 89 and.1lought tobe.

On the rear side (north side) of the middle piece, 0, the hemerophora isattached. This consists of a bearer, G, secured to the side of the plate0, said bearer being provided with a semicircular cut, as shown in Fig.2. On

the inner side of this cut is a groove all around the are, which admitsan are, H, called the horologet. This are is made of brass or othersuitable material, and bears upon it the description of the hours of theday, and is for this reason called horologet. The bearer might alsoproperly be called equator, for the reason that it has to be set, bymeans of the revolving middle piece, O. in accordance with the celestialequator, it being exactly perpendicular, or at right angles with themiddle piece, 0. The division of the are H regarding the inscription ofthe hours is simplythis: 6 oclock of the morning and 6 o clock of theevening are distant from each other, so that a straight line drawn from6 to 6 passes through the center of the arc. The remaining hours are 15distant from each other. Thus if we call 6 oelock of the morning degree0, 7 ocloek comes on degree 15. 8 on 30, &c., 12 oclock on degree 90.The horologet is more than a semicircle, in order to gain space for theinscription of at least one hour more for the morning and one for theevening. Thus provision is made for the summer season, when the day islonger than twelve hours. The horologet H can be shifted around its owncenter. The motion is, however, very small, amount ing in all only tothe space which half an hour,

or, more accurately, thirty-one minutes, on the horologet occupy. Theend of this motion is to set. the horologet so that it indicates themiddle time, or the time of a correct clock, for the sun time differsmore or less from the latter, itbeing sometimes too slow, sometimes toofast.

I represents the meridional gnomon or in dicator, consisting of a'brassplate, (see Fig. 5,) the upper end, (I c (I, being an arc, the center ofwhich is i. As it is represented in the drawings, the arc extends onboth sides of e a little over thirty degrees. Of strict necessity theyare, however, only twenty-three and onehalf degrees on both sides, thesebeing the amount of the declination of the sun; but it seems preferableto let the are ext-end farther, for the sake of obtaining a full anddistinct shade cast on the horologet, especially at the time of thesolstices. The radius c has to be obtained thus: Take the radius of thehorologet, .add to it one thirty-second part of its own length. I. Thereason for this will be hereinafter set forth. The gnomon has to be setthus: The lined c has to stand perpendicular 011 the horologet, passingthrough its center. The line f f bisects the horologet at right angles,and,

moreover, touches-the surface of the inner side of the horologet, sothat the pointi touches the middle of it, or, more accurately, z touchesthat circular line passing along the middle of the horologet, on whichthe divisions of the hours are marked.

It may here be observed that the shape of the bearer or equator G is notessential, only so that in all cases it is perpendicular to and The sumis the radius of the gnomon.

revolves with the middle piece, 0; that it bears around in thisrevolution the horologet H, giving to it the direction described above;that it admits the horologet to be shifted around its own center, andthat it carries along, when turned around together with the horologet,.also the gnomon I and the appara tus required for shifting thehorologet. This apparatus will be hereinafter described.

The advantages of thehemerOphOra are that it shows at everyseason of theyear, at

every time of the day, at every place on the globe the correct time-thatis,the time which a correct clock shows. It might be'asked whether therefraction of thesunbeams'in our atmosphere would not affect thehemerophora, preventing it from showing the correct time. It does not,since provision is made for that.

The gnomon Iis, as described above, shaped so that the'radius'of the'arcd 6 dis by one thirty-second greater than the radius of the horologet.

The effect of this is that on the morning the shadow is cast backward,on the evening forward. If, for instance, 011 the 21st of March the runrises in fact, not in'appearano e, at 6 o clock, (sun time,) the shadowof the rising sun is cast backward by a few minutes, showing 5.53. Asthe apparent sun, so

to speak, rises over the horizon, little by little the shadow falls on 6-o clock at the very point of timewhen the real sun rises. Under thebearer G is a box, J, of semicircular shape, having upon the inside ofits rim and on its bottom the days in the year, so arranged that thedays, when there is; no variation" between the sun and clock-time, willbeimlnediately below the center of the gnomon I, and the names -or dateswill come in regular rotation. on each side of the center--- that is,one sidefor the sun time becoming slower and the other side 'for'itbecoming faster, only such dates,*however, being put in where thedifference is not less than one min ute from the preceding date. I

In the bearer G is hung a finger, m, pointing toward the names in thebox J. This finger is, by suitable mechanical devices, con- 1 nectedwith the horologet H in such a manner that, moving it (the finger) onespace, the I horologet will be turned around its own center the distanceof one minute. By this means I am enabled at anytime so reset thehorologet that it will show the exact time;

Having thus fully described my invention, Y what Lclaim as new, anddesire to secure by Letters Patent, is p 1. Theequatorial gnomon E, incombination with the eliseologet D and revolving 4. The combination ofthe bed A, end pieces,

B B, plate 0, pins (1 a, fingers b b, arcs L L, cliseologetD, gnomon E,bearer G, horologet H, and gnomon I, all constructed and arranged asdescribed, substantially as and for the purposes herein set forth.

In testimony that I claimthe foregoing I have hereunto set my hand this1st day of February, 1870. a a

L. IGNATIUS TRUEG.

Vitnesses:

J. M. STooPs, C. L. EVERT.

